Optimists, take comfort: this is actually an improvement; last time the report was published, in 2009, the country received a D.

The ASCE reckons America would need $3.6 trillion worth of investment to bring infrastructure up to speed by 2020, significantly more than the $2 trillion currently dedicated.

Compared to measures spanning water and environment, transportation, public facilities, and energy, inland waterways and levees came in last, both with a D- grade. The backbone of the country's freight network, these waterway systems have not been updated since the 1950s, and projected investment is stagnant. While levees were said to have prevented more than $141 billion in flood damages in 2011, many of the country's levees are aging, unreliable, and would cost around $100 billion to repair.

On the brighter side, our railways and bridges earned a C+, the highest marks given out. While the overall number of structurally deficient bridges in the country continues to fall, the average age of the country's 607,380 bridges is 42 years, and the Federal Highway Administration estimates $20.5 billion would need to be invested annually to eliminate the backlog by 2028 -- compared to the $12.8 billion current annual spending.

As rail gains popularity as a viable - and energy-efficient - transport option for both freight and passengers, Amtrak has nearly doubled its ridership since 2000, with a ridership of 31.2 million passengers in 2012. Since 2009, capital investment in railroads has exceeded $75 billion - with investment actually increased during the recession.

Left untended, infrastructure lapses can significantly slow down the economy. Perhaps these grades will help spur investment in the areas that need it most.